This invention relates to arm rests and more particularly to arm rests associated with generally vertical panels in an automobile, such as automotive door panels.
Current arm rests for vertical automotive panels are generally rigid structures that include a semi-rigid urethane foam pad or cushion for softness. The semi-rigid urethane foam pad is typically an intermediate layer in a construction that includes a flexible outer skin and a rigid substrate or insert. The arm rest can be a separate structure that is attached to the automotive panel or it can be integrated into the automotive panel itself.
The primary function of an arm rest is provide a shelf that supports the forearm of a seat occupant comfortably. In order to function properly, the arm rest necessarily protrudes laterally from the vertical panel that it is associated with. Consequently the arm rest has been recognized as a potential source of injury to the seat occupant in a side impact collision for a long time. The prior art constructions discussed above have a common drawback with respect to side impact collisions in that there is very little absorption of the side loads by the semi-rigid foam cushion before the seat occupant encounters the rigid substrate.
A proposed solution to this side impact problem is to provide an arm rest that collapses in response to side loads. Of course these laterally collapsible arm rests must have sufficient vertical strength for use in supporting the arm loads that can be generated by the seat occupant. Moreover the laterally collapsible arm rests ordinarily must also retain sufficient lateral strength for use in opening and closing an automobile door because arm rests are associated with automotive door panels most of the time. Proposals for laterally collapsible arm rests are already known from the following patents.
U.S. Pat. No. 3,400,979 issued to Ivor F. James Sep. 10, 1968 discloses a safety arm rest in which a honeycomb filler of metal, paper or plastic is secured to a metal back up plate. This sub-assembly is inserted into a vinyl skin which is then filled with polyurethane foam filler material. The honeycomb filler has two rows of thin walled cells that are vertically elongated. These cells are filled with the polyurethane foam filler material either before or after the subassembly in inserted into the vinyl skin. The patent specification states that it is desirable to place a thin sheet of paper or fiberboard across the top of the honeycomb cells prior to insertion of the assembly. According to the patent specification, the arm rest is collapsible laterally but not vertically because of the orientation of the honeycomb cells and the sheet metal is easily distortable so that it is not a source of injury.
This arm rest is complicated as well as difficult and expensive to manufacture. Moreover, the thin sheet of paper or fiberboard across the top of the honeycomb cells appears necessary to avoid vertical collapse. This sheet adds manufacturing expense and contributes to the manufacturing difficulty by complicating the foaming operation.
U.S. Pat. No. 3,387,881 issued to George R. Stepanek and William H. Terrell Jun. 11, 1968 discloses a collapsible arm rest having a foldable or collapsible insert that is formed from a single sheet of polypropylene with living hinges, folded into a triangular shape and attached to an attaching plate. The insert is disposed in a decorative vinyl skin where it is yieldingly held in the full-line position shown in FIGS. 2 and 3 of the patent by foam which surrounds and fills the interior of the insert. According to the patent specification, the insert supports vertical loads of 100 psi applied to the top of the arm rest due to the generally triangular form of the insert. Also according to the patent specification, the insert folds up or collapses in the lateral direction when side loads of 15 psi are applied to the side of the arm rest due to the location of the hinges.
This arm rest also is difficult to manufacture because the insert must be folded precisely and maintained in this folded shape during the foaming process which surrounds and fills the interior of the insert with foam. Moreover, the generally triangular shape of the insert that is necessary to resist vertical loads also limits the amount of lateral collapse that is possible considerably primarily because of the unyielding nature of the inclined under panel that forms part of the insert.
U.S. Pat. No. 3,620,566 issued to Jacky Leconte Nov. 16, 1971 discloses an arm rest comprising a flexible body of cellar plastic material fitted to a sheet metal pressing that is secured to a longitudinal base plate. The sheet metal pressing comprises two lateral substantially V-shaped bent portions which are distorted in the case of shock. The bent portions have bent lugs that support a cardboard sheet and a semi-rigid foam or cellular padding element covered with the flexible body. A pair of tie members connect the front of the pressing to the base plate to prevent distortion when the arm rest is pulled by a user.
This arm rest is also complicated as well as difficult and expensive to manufacture. Moreover, the cardboard sheet supported on the sheet metal pressing which appears necessary to avoid vertical collapse adds manufacturing expense, contributes to the manufacturing difficulty by complicating the foaming operation and hinders lateral collapse of the arm rest. Furthermore the tie members that are necessary to prevent distortion when the arm rest is pulled hinder the collapse of the sheet metal pressing.